Shielded electrical connector systems are used widely in such applications as telecommunications equipment, computers and other digital information systems, and the like. The electrical circuitry in such applications include electrical cables having a plurality of electrically conductive leads surrounded and protected by an electrically conductive shield, such as a braid, foil or the like. In most such applications, it is necessary to shield the signal-carrying circuits to avoid electromagnetic interference caused by energy generated outside of as well as inside the system, and/or to avoid radio frequency interference entering the system.
Many such electrical connectors are used in conjunction with systems which incorporate printed circuit boards to which the connectors are surface-mounted or with panels having apertures through which the connectors are mounted. In fact, there are applications where individual connectors must be mounted both to a printed circuit board and through an adjacent panel. Often, both the board and the panel have ground planes or plates to which the connectors are conductively coupled. The coupling usually is through the shield of the connectors.
One type of shielded electrical connector assembly is a connector which is "box" or rectangularly shaped and includes a rectangularly shaped dielectric housing which is substantially surrounded or covered by a stamped and formed sheet metal shield Examples of such connectors are shown in U.S. Pat. Nos. 4,679,879 and 5,083,945, which are assigned to the assignee of the present invention.
Such prior art shields are manufactured by blanking, die-cutting or stamping, and forming the box-like shield, and wherein open seams result at various locations in the shield, such as at certain corners or edges of the shield. In most applications, such constructions provide adequate electromagnetic and radio frequency interference protection such that transmission of signals through the connectors are not affected However, when the electromagnetic fields are very strong, even small openings as presented by open seams in the stamped and formed shield allow leakage which may interfere with the transmission of electrical signals.
Heretofore, open seams in such shields have been closed by solder or other flowable materials. Another approach is shown in U.S. Pat. No. 5,136,119 to Leyland, dated Aug. 4, 1992. In that patent, metallized Velcro strips are used to close the open seams of a box-like shield. In shielded electrical connectors, the shields contribute considerably to the total cost of manufacturing the associated electrical connectors, and such approaches to closing open seams in the shields add still further costs and additional steps in the manufacturing process.
This invention is directed to solving the problems outlined above by providing a stamped and formed metal shield which is void of open seams, yet the shield is formed from a one-piece blank of material. No additional steps are required in fabricating the shield, other than the normal stamping and forming operations, and there are no significant increase in costs of manufacture.